The present invention relates generally to semiconductor packaging, and, more particularly, to a method of assembling pressure sensor packages.
Pressure sensors are used in a variety of applications such as industrial, automotive and medical applications. Such sensors typically include a diaphragm at one end that is brought into contact with a media such as a fluid in an environment of interest. During operation, the diaphragm is displaced due to the pressure of the media.
The diaphragm is mechanically coupled to a pressure sensor element, which measures the pressure of the media in the environment based on a physical parameter such as compression, displacement or deformation of the pressure sensor element, with the media pressure being transferred to the pressure sensor element from the diaphragm either directly, or through a mechanical coupling.
The pressure sensor element may include, for example, piezoelectric or piezoresistive crystals to provide an electrical signal indicative of the sensed pressure. One traditional way of packaging the pressure sensor includes leaded packages where the pressure sensor element, diaphragm and the leads are packaged with a lid to cover the pressure sensor element and the diaphragm. However, a problem faced by such packaging techniques is that there is a risk of diaphragm damage because the pressure sensor element is disposed face-up directly below a vent hole. Further, the metal lid used to protect the pressure sensor element adds additional cost to the package and also the package is constrained by the thickness of the lid.
Accordingly, it would be advantageous to be able to efficiently package sensor devices that do not require a lid and the risk of damage to the sensor element and the diaphragm is reduced.